1. Field of the Invention
This invention relates to an electrical adjusting apparatus which may be used for supplying a desired electrical energy value (e.g. voltage) to a device such as a liquid-crystal driving device in a camera.
2. Description of the Prior Art
In a liquid-crystal driving device provided in a camera, if the power source's voltage changes owing to the operation of a heavy load such as motor or a DC/DC converter in the camera, the voltage for driving the liquid-crystal driving device changes correspondingly, resulting in difficulty in controlling the turning on and off of segments of the liquid-crystal display element and, hence, a reduction in the accuracy of the display. Conventionally, to cope with this problem, a constant-voltage generating circuit is usually provided. However, due to manufacturing errors there is a certain degree of dispersion in the voltages generated by constant-voltage generating circuits, particularly those having driving sections constituted by ICs. It is difficult to limit this dispersion, particularly when the constant-voltage generating circuits are designed to have temperature compensation characteristics and are provided in dynamic drive systems. Nevertheless, this dispersion must be reduced.
Also there is a known device in which an external adjusting circuit element, such as a resistor, is provided to enable the liquid-crystal driving device to be supplied with a desired voltage. However, this method increases the number of parts and is disadvantageous in terms of space reduction. There are other methods, such as one in which a soldered resistor is replaced with one selected from resistors of different values, so as to obtain the desired voltage, or one in which a factory-adjusted resistor is used. However, these methods are also disadvantageous because they are time-consuming or they cannot ensure reliability during a long-term use.
Japanese Laid-Open Patent Application No. 54-10932 relates to a camera having an electrically erasable non-volatile memory which stores film sensitivity information but this patent does not disclose the use of an electrically erasable non-volatile memory as a means for memorizing manually adjustable data in a system for adjusting voltage or energy.